PROJECT SUMMARY Alcohol misuse among young adults in the U.S. is a significant public health concern. Protective behavioral strategies (PBS) are cognitive-behavioral strategies used before, during, or immediately after drinking to reduce alcohol use, intoxication, and/or alcohol-related harms. Using PBS appears to be an effective means of harm-reduction, though PBS-based interventions are unlikely to have reached their full potential. While much is known about motivation for drinking, surprisingly little is known about motivation for engaging in PBS. Better understanding of motivation for PBS use can inform the development of novel interventions that motivate young adults to use such behaviors. Self-determination theory (SDT) is a general theory of human motivation that has been applied to understand a wide range of health-promoting behaviors, though its application to alcohol research has been limited. SDT proposes that there are different types of motivation that vary in the extent to which they are self-determined. For example, people may engage in a behavior because they feel pressured to do so (i.e., controlled motivation) or because they value the behavior (i.e., autonomous motivation). According to SDT, autonomous motivation is more likely to result in the initiation and maintenance of health-promoting behaviors than controlled motivation. Autonomous motivation is posited to be facilitated by environments that satisfy the basic psychological needs for autonomy, competence, and relatedness. Our objective in this proposal is to use an ecological momentary assessment (EMA) design to comprehensively investigate the tenets of SDT to better understand PBS use. Specifically, we will retain a racially/ethnically diverse, sex-balanced sample of college student (n = 90) and non-college attending young adult drinkers (n = 90) who are self-determined (n = 30/30; highest in autonomous motivation, lowest in amotivation), highly motivated (n = 30/30; high in both autonomous and controlled motivation), and low/amotivated (n = 30/30; relatively high on amotivation and low on both autonomous and controlled motivation) to use PBS to complete a 4-week EMA study. This innovative design will allow us to efficiently evaluate the tenets of SDT as applied to using PBS at both the within-subjects (Aim 1) and between-subjects level (Aim 2), clarifying novel targets for alcohol interventions that could result in sustained behavioral change. Each aspect of the research design was chosen deliberately to enhance the applicant?s training. Potential moderators of the within-subjects associations between SDT constructs and alcohol-related outcomes will be examined to help inform future intervention tailoring (Exploratory Aim).